package com.common.util;
import com.common.base.BaseEnum;
import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Objects;

/**
* @version: V1.0
* @author: szw
* @className: PasswordUtil
* @packageName: PasswordUtil
* @description: 密码处理工具类
* @data: 2021-1-19 
**/   
public class PasswordUtil {

    /**
     * 使用:
     *      直接使用即可,至于具体参数,看下面方法的说明即可;
     *      1. PasswordUtil.MD5Encode();  MD5不可逆简单加密:散列函数-基于HASH算法的编码
     *      2. PasswordUtil.AESEncrypt(); AES加密
     *      3. PasswordUtil.AESDecrypt(); AES解密
     *      4. PasswordUtil.parseByte2HexStr(); 二进制到16进制
     *      5. PasswordUtil.parseHexStr2Byte(); 16进制到2进制
     */
    // 16进制的字符数组
    private final static String[] hexDigits = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};

    /**
     * @param source    原字符串
     * @param encoding  指定编码类型
     * @param uppercase 是否转为大写字符串
     */
    public static String MD5Encode(String source, String encoding, boolean uppercase) {
        String result = null;
        try {
            result = source;
            // 获得MD5摘要对象
            MessageDigest messageDigest = MessageDigest.getInstance("MD5");
            // 使用指定的字节数组更新摘要信息
            messageDigest.update(result.getBytes(encoding));
            // messageDigest.digest()获得16位长度
            // result = parseByte2HexStr(messageDigest.digest());
            result = byteArrayToHexString(messageDigest.digest());

        } catch (Exception e) {
            e.printStackTrace();
        }
        return uppercase ? result.toUpperCase() : result;
    }

    /**
     * AES 加密
     *
     * @param content 需要加密的内容
     * @param aesKey  加密密钥
     * @return
     */
    public static byte[] AESEncrypt(String content, String aesKey) {
        try {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            kgen.init(128, new SecureRandom(aesKey.getBytes()));
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            Cipher cipher = Cipher.getInstance("AES");// 创建密码器
            byte[] byteContent = content.getBytes("utf-8");
            cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
            byte[] result = cipher.doFinal(byteContent);
            return result; // 加密
        } catch (NoSuchAlgorithmException | BadPaddingException | IllegalBlockSizeException | UnsupportedEncodingException | InvalidKeyException | NoSuchPaddingException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 解密
     *
     * @param content 待解密内容
     * @param aesKey  解密密钥 秘miyao
     * @return
     */
    public static byte[] AESDecrypt(byte[] content, String aesKey) {
        try {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            kgen.init(128, new SecureRandom(aesKey.getBytes()));
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            Cipher cipher = Cipher.getInstance("AES");// 创建密码器
            cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
            byte[] result = cipher.doFinal(content);
            return result; // 加密
        } catch (NoSuchAlgorithmException | NoSuchPaddingException | BadPaddingException | IllegalBlockSizeException | InvalidKeyException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 将二进制转换成16进制
     */
    public static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }

    /**
     * 将16进制转换为二进制
     */
    public static byte[] parseHexStr2Byte(String hexStr) {
        if (hexStr.length() < 1)
            return null;
        byte[] result = new byte[hexStr.length() / 2];
        for (int i = 0; i < hexStr.length() / 2; i++) {
            int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
            int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2), 16);
            result[i] = (byte) (high * 16 + low);
        }
        return result;
    }
    //byte转16进制
    private static String byteArrayToHexString(byte[] bytes) {
        StringBuilder stringBuilder = new StringBuilder();
        for (byte tem : bytes) {
            stringBuilder.append(byteToHexString(tem));
        }
        return stringBuilder.toString();
    }
    //16进制转byte[]
    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0) {
            n = 256 + n;
        }
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

    /**
     * 密码加密-默认密码
     *  1. ask加密处理
     *  2. 在转换位16进制字符串
     * @return
     */
    public static String generatePwd(){
        byte[] encrypt = PasswordUtil.AESEncrypt(BaseEnum.DEFAULT_PASSWORD.getCode(), BaseEnum.PASSWORD_KEY.getCode());//加密
        String strHex = PasswordUtil.parseByte2HexStr(Objects.requireNonNull(encrypt));
        return strHex;
    }

    /**
     * 密码加密
     *  1. ask加密处理
     *  2. 在转换位16进制字符串
     * @return
     */
    public static String generatePwd(String pwd){
        byte[] encrypt = PasswordUtil.AESEncrypt(pwd, BaseEnum.PASSWORD_KEY.getCode());//加密
        String strHex = PasswordUtil.parseByte2HexStr(Objects.requireNonNull(encrypt));
        return strHex;
    }
}
